package JSE_02.Map.Demo06;

import java.util.HashMap;
import java.util.Hashtable;

public class HashTable {
    public static void main(String[] args){
        HashMap<String,String> map=new HashMap<>();
        map.put(null,"a");
        map.put("b",null);
        map.put(null,null);
        System.out.println(map);

        System.out.println("==============");
        Hashtable<String,String> table=new Hashtable<>();
//        table.put(null,"a"); // 不能存储null
//        table.put("a",null);
//        table.put(null,null);
        System.out.println(table);
    }
}
